Reiteration frequency of duck haemoglobin genes

BECAUSE of the large DNA content of the eukaryotic genome1,2 and the existence of reiterated DNA sequences3,4, it has been thought that the DNA sequences which specify protein structure are present in many copies per genome. The idea is not immediately compatible with the simple dominance relationships which alleles at many genetic loci show. A special mechanism has been proposed to overcome this difficulty5, which can also be surmounted in many other ways. From a theoretical standpoint, the question of whether DNA sequences which specify protein structure are reiterated is still open.